Plane and the like for aeroplanes.



A. A. HOLLE.

PLANE AND THE LIKE FOR AEROFLANES.

APPLIQATION FILED DEC- 22, I916- Patented May 8, 1917.

INVENTOR.

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ALEXANDER ALBERT HOLLE, OF THAMES DITTON, ENGLAND, ASSIGNOR TO THEVARIOPLANE COMPANY LIMITED, OF LONDON, ENGLAND.

PLANE AND THE LIKE FQR AEROPLANES.

Application filed. December 22, 1916.

To all whom it may concern:

Be it known that l, ALEXANDER ALBERT Home, a subject of the Queen of theNetherlands, residing at Bisham Lodge, Speer Road, Thames Ditton, in thecounty of Surrey, England, have invented certain new and usefulImprovements in and Relating to Planes and the like for Aeroplanes, ofwhich the following is a specification.

This invention relates to planes, wings, or the likehereinafter referredto as aerofoilsof aeroplanes of the variable camber type, whether samebe the main supporting planes or auxiliary planes employed forcontrolling and stabilizing purposes, and it consists of an improvedconstruction which has for its object to extend the range of speeds ofthe machine in the horizontal and vertical planes, to extend its rangeof angles of ascent and descent, to extend its vertical range or maximumattainable altitude, to increase its efficiency as measured by itscapacity for carrying a maximum load with a minimum expenditure ofpower, to improve its stability and maneuvering qualities, and lastly tobalance the forces acting on the surfaces of the aerofoil so as toreduce to a minimum the efiort necessary for its control.

The object of varying the camber of an aerofoil is to vary its angle ofincidence whereby its lifting power is increased. The usual way ofincreasing the angle of incidence is by tilting it, either with themachine as a whole, or relatively to the body or fuselage of themachine. The objection to tilting the areofoilwhich is mechanically themost simple meth0'dis that the camber of the aerofoil-which is apermanent onecan only be best suited to one particular angle ofincidence, and although it permits the aerofoil to deal with a deepstratum of air (at a large angle) for a given chord and to deflect alarge mass of air it does so more or less inefficiently at all anglesbut one. Furthermore, as is well known, the result of varying the angleof incidence by tilting the aerofoil is that the center of pressuremoves considerably and in an unstable direction. This, apart fromaerodynamical disadvantages, makes the balancing of the efiort requiredfor manipulation difficult, if not impossible, in constructions in whichthe incidence is varied relatively to the body of the machine.

Specification of Letters latent.

Serial No. 138,464.

Another way of increasing the angle of incidence is to vary the camberor curvature of the aerofoil. This has been carried into effect in manyways, for instance by curving the aerofoil throughout its entire length,by flexing the trailing edge of the aerofoil downward, by flexing theleading or entering edge of the aerofoil downward, and by flexing boththe leading and the trailing edges downward either independently or atthe same time. In all these constructions the thickness of the aerofoilthroughout its entire length remains con stant, and although they enablean increased stratum of air to be dealt with they only slightly increasethe angle of incidence and therefore the lifting power, and have thesame disadvantages as the tilted aerofoil in that the forces requiredfor manipulation cannot be balanced.

According to the present invention, the aerofoil is constructed with aflexible rear or trailing edge and a rigid front or entering edge, saidfront edge having a continu ous undeformable under surface and acontinuous deformable upper surface so that the camber of said uppersurface can be varied. The flexible trailing edge and the deformableupper surface of the front or entering part are so connected that at thesame time that the rear or trailing edge is flexed downward the camberof the upper surface of the front or entering part of the aerofoil isincreased, the under surface of the front or entering part remainingunchanged. The result of this is that the thickness of the aerofoil atits forward part is increased so that at the same time that its angle ofincidence is increased its thickness at its front or entering edge isalso increased, whereby the depth of the stratum of air swept by theaerofoil and the amount of air deflected is materially increased, saidamount of deflected air being dealt with in the most eflicient mannerfor the angle at which it is deflected.

- The mechanisms employed to efiect the flexing of the trailing edge andthe variation of the camber cf the upper surface at the front orentering edge are controlled by a balancing beam so that as the camberof the upper surface is increased the trail ing edge is flexed downwardand vice versa, whereby the positive pressure on the under side and thenegative pressure on the upper side of the trailing portion of theaerofoil is counterbalanced by the negative pressure on the leadingportion of the upper surface of said aerofoil.

In the accompanying drawing which shows by way of illustration oneconstruction for carrying this invention into effect:

Figure 1 is a diagram viewdivided into two parts-showing the aerofoil inits stream-like form, and

Fig. 2 is a similar view showing the aerofoil in its cambered form.

In both views similar parts are marked with like letters of reference.

The aerofoil comprises a rigid main frame consisting of a plurality oflongitudinally arranged spars 0, one of which is shaped to form the nose(1 of the front or entering edge a, and an articulated frame consistingof a pair of pivoted elements 9 and g The spars e are carried by platesf, one located at each end of the aerofoil and such others interposed asthe length of the structure demands, and said plates carry a series offlexible upper and lower ribs h adapted to carry the material employedfor the surfaces of the aerofoilnot shown in the draw ingsand arrangedtransversely in respect to the main frame, and two series oflongitudinally arranged girders 7s and 70 to which said ribs are fixed.

The flexible ribs h at the ends of the aerofoil are arranged over theend plates f and the intermediate ones are spaced at suitable distancesapart. The girders 70, preferably are so arranged that at all curvaturesthat the upper surface of the aerofoil at its forward part can assume,they remain at right angles to a line tangential to the curved surface.These girders are carried on a plurality of levers m which are pivotedto the plates f. The girders 70 are carried by brackets 72. which carrypins n which engage slots g in the plates g and 9 On plates 7 arepivoted rocking beams 7- mounted on a common shaft 1 for simultaneouslyoperating the mechanisms for lifting the girders is to vary the camberof the upper surface 0 of the aerofoil at its front or entering edge a,and for flexing both the upper and lower surfaces of the rear ortrailing edge 6 of the aerofoil.

The mechanism for varying the camber of the upper surface of theaerofoil comprises the levers m which are pivoted to the main structureat one end and to the girders 74 at the other end, the lengths of saidlevers and their points of pivot being so arranged as to give them thenecessary differential movement to produce the required alteration inthe camber of the upper surface of the aerofoil and links 0 by which theforward ends of the beams r are coupled to two of the levers 00. Eachseries or group of levers amay be coupled together if desired. Themechanism for flexing the articulated frame forming the trailing edge ofthe aerofoil consists of links .9 which are pivoted to the main frame atpoints above the points of pivot of the beams r and convenientlyasshownat the same points as one of the levers 0c is pivoted, and of linkst which connect the plates 57 with offset arms 1 at the rear ends of thebeams 7, said rear ends of said beams being pivoted to the forward endsof the plates 9.

It will be understood that the mechanism at each end of the aerofoil isthe same and that the connections between said mecha nisms areessentially the girders is and k and the shaft 7. When intermediateplates f are employed intermediate mechanisms may also be employed, inwhich case means other than the girderssuch for instance ascontinuations of the pivots of the various leversmay be employed forconnecting the various mechanisms together.

The actual surfaces of the aerofoil are formed of the usual materialwhich is car ried by the flexible ribs, and to provide for the increaseddistance on the upper surface of the aerofoil between the front and thetrailing edges thereof when the camber is increased and to preserve thecontinuity of said surface, the upper part of each flexible rib h isarranged to overlap at one part as shown, said overlapping part-s 7L andh being guided in relation to one another in suitable guides such as itand the surfacing material is arranged accordingly.

The motion necessary to actuate the two I mechanisms is imparted to thebeam 1 on the end plate 7 nearest to the fuselage of the machine, but itmay also be imparted to any other convenient part or parts of themechanisms in couple with said beam.

In the construction hereinbefore described with reference to theaccompanying drawing, the actual shapein transverse section of theaerofoil is determined to some extent by the flexibility 0f the ribs.This in practice would necessitate said ribs being very carefully gradedand the aerofoil would only remain perfect so long as no deteriorationof the material of which the ribs are made takes place. The preferredconstruction is one in which the ribs are flexed from one prein the sameplace relatively to the center of gravity, whereby the aeroplane isautomati cally balanced in flight at all speeds and a consequentialimprovement in its stability is obtained.

An aeroplane fitted with aerofoils constructed and arranged according tothis invention has the advantage that the fuselage will always remainpractically parallel to the line of flight, so that the propeller isalways working to the best advantage, 2'. a. with the plane in which theblades rotate constantly at right angles to the direction or line offlight.

It will be appreciated that the suction or negative pressure on thecamber of the upper surface of the aerofoil near its front or enteringedge will facilitate the operation of increasing the camber, and thatboth the suction above the trailing edge of the aerofoil and thepressure beneath same will tend to oppose the downward flexing of saidedge, so that by suitably apportioning these functions andinterconnecting the operating mechanisms the opposing forces can be moreor less completely balanced, whereby the effort of control is reduced toa minimum.

The variations of the shape, section and configuration of the aerofoilsmay also be utilized either exclusively or partially for directional orlateral control or both.

What I claim as my invention, and desire to secure by Letters Patentis 1. In an aerpfoil for aeroplanes, the combination of a rigid framecarried by the fuselage of the machine, a nose piece carried by saidframe forming the front or entering edge of the aerofoil, a continuousor unbroken undeformable under surface carried by said frame, acontinuous or unbroken deformable upper surface carried by said frame,and a flexible trailing edge carried by said frame.

2. In an aerofoil for aeroplanes, the combination of a rigid framecarried by the fuselage of the machine, a nose piece carried by saidframe forming the front or entering edge of the aerofoil, an articulatedframe connected to said frame, a continuous undeformable under surfacecarried by the rigid frame, a continuous deformable upper surfacecarried by the rigid frame and mechanism coupling the articulated framewith the deformable upper surface of the forward part of the aerofoil,so that as the trailing edge of the articulated frame is flexed downwardthe camber of the deformable upper surface is increased and as thetrailing edge is flexed upward the camber of the deformable uppersurface is decreased.

3. In an aerofoil for aeroplanes, the combination of a rigid framecarried by the fuselage of the machine, a nose piece carried by saidframe and forming the front or entering edge of the aerofoil, anundeformable under surface carried by said frame, a

deformable upper surface carried by said frame, an articulated frameforming a flexible trailing edge carried by said frame, a rocking beammounted on the rigid frame, mechanism operated by one end of the rockingbeam for flexing the trailing edge, mechanism operated by the other endof the rocking beam for raising and lowering the upper surface of thefront or leading part of the aerofoil so that as the trailing edge isflexed downward the camber of the upper surface is increased and as thetrailing edge is flexed upward the camber of the upper surface isdecreased.

4. An aerofoil comprising a rigid frame carried by the fuselage of themachine, an articulated frame coupled to and forming an extension of therigid frame, a series of flexible upper and lower ribs transverselyarranged in respect to and carried by said frames, a series oflongitudinally arranged girders connected to said ribs, mechanism forraising and lowering said girders and ribs, mechanism for flexing theelements of the articulated frame, rocking beams pivoted on the rigidframe said beams being connected at their front ends to the mecha nismfor raising and lowering the upper surface of the front part of theaerofoil and at their rear ends to the mechanisms for flexing thearticulated frame forming the rear or trailing edge of the aerofoil.

5. An aerofoil comprising a main rigid frame carried by the fuselage ofthe machine and consisting of two or more plates and a plurality oflongitudinally arranged spars, an articulated frame consisting of aplurality of elements pivoted together said frame being coup-led to themain or rigid u frame, a series of flexible upper and lower ribstransversely arranged in respect to and carried by said frames, a seriesof longitudinally arranged girders connected to said ribs, aseries oflevers pivoted to the rigid frame and connected to the upper parts ofthe flexible ribs, links connecting the elements of the articulatedframe to the main frame, rocking beams pivoted to the main frame theforward parts of said beams being connected to the levers operating theupper surface of the forward part of the aerofoil and the rear parts ofsaid beams being connected to the inner elements of the articulatedframe forming the flexible trailing part of the aerofoil.

6. An aerofoil comprising a rigid frame carried by the fuselage of themachine and consisting of ,a plurality of plates and a plurality oflongitudinally arranged spars, an articulated frame consisting of aplurality of elements pivoted together said frame being pivotallyconnected to the rigid frame, a plurality of flexible upper and lowerribs transversely arranged in respect to and carried by said frames, aplurality of longitudinally arranged girders connected to said ribs, aplurality of levers pivoted to the rigid frame and connected to theupper parts of the flexible ribs, rocking beams pivoted on the rigidmain frame and having cranked arms at their rear ends said beams beingpivoted at their rear ends'to the front elements of the articulatedframe, links con- 10 necting the cranked arms of each of the elements ofthe articulated framebelow their point of pivot to the rocking beamstothe rigid main frame above the points of pivot of the rocking beams tosaid frame, couplings between the elements of the articulated frame andthe flexible ribs of the trailing edge of the aerofoil, and couplingsbetween the rocking beams and the levers supporting the flexible ribs ofthe forward part of the aerofoil.

In testimony whereof I have signed my name.

ALEXANDER ALBERT HOLLE.

